The present invention relates to sorbitol and its use in confectionary compositions.
Sorbitol has been utilized as a plasticizer and bodying agent in many products, a principal use presently being as a sweetner or excipient in confections or pharmaceutical tablets as set forth in U.S. Pat. No. 3,200,039. However, the hygroscopic nature of sorbitol may limit the conditions under which a tablet press, used to prepare lozenges or tablets, can be operated without jamming. Further, problems may exist with respect to preparing a sorbitol product which has sufficient crystallinity to be tableted.
Amorphous uncrystallized sorbitol, or "glass" is characterized by an absence of a significant heat of fusion. The large percentage of "glass," e.g. about 40%, in many commercially available sorbitol products results in a material which has a tendency to soften when tableted, necessitating high pressures to obtain satisfactory lozenge hardness, if such can be obtained at all.
In order to prepare sorbitol with a high crystallinity, methods including the cooling of a hot solution or melt with added sorbitol crystals have been disclosed in U.S. Pat. Nos. 2,483,254; 2,594,863; 3,308,171 and 3,330,874, German Auslegeschrift No. 1,115,726, Japanese Patent Application No. 1970-119151 and Patentschrift No. 83,341 of the German Democratic Republic. Other crystallization or solidification techniques are described in U.S. Pat. Nos. 2,315,699 and 2,566,410 as well as in German Patentschrift No. 76,487.
A procedure for preparing a substantially crystalline sorbitol is disclosed in my U.S. Pat. No. 3,973,041. The sorbitol produced comprises at least about 80% of the gamma sorbitol polymorph and the method involves a simultaneous mixing and cooling of a sorbitol magma in a continuous mixer such as that described in U.S. Pat. No. 3,618,902. Other mixing or kneading apparatuses are set forth in U.S. Pat. Nos. 3,195,868; 3,198,491; 3,318,606; 3,419,250; 3,423,074; 3,490,750; 3,873,070 and 3,900,187. The compounding of various food compositions is reported in U.S. Pat. Nos. 2,847,311; 3,694,227 and 3,806,617.
Highly crystalline sorbitol, such as that described in U.S. Pat. No. 3,973,041 may not meet tablet manufacturers needs since some of the more crystalline sorbitol tends to have a limited degree of crystal copenetration under pressure during tableting. Added pressure may cause "capping", the separation of tablet into two separate pieces. This problem is particularly encountered when the formulator uses a weight-to-weight substitution of a highly crystalline sorbitol with a dense crystal matrix for a conventional sorbitol preparation, for example, sorbitol with a low degree of crystallinity. Further, when the dense crystalline sorbitol is used as a weight-to-weight substitution in chewing gum formulations, it may be found that the gum is too soft to process in an efficient manner and an increased amount of crystalline sorbitol with a corresponding decrease in the volume of plasticizer is required to achieve the desired consistency.
It is therefore an object of the invention to provide a gamma sorbitol product, at least about 80% crystalline, which possesses excellent tableting characteristics and which will also increase the shelf life of sorbitol-containing chewing gums produced therewith, while at the same time allowing the formulator to make a substantially weight-to-weight substitution for the conventional crystalline sorbitol which is about 60% to 90% crystalline and which contains one or more crystalline polymorphs.
As used in the present specification, "sorbitol" is inclusive of the compound sorbitol with or without minor amounts of mannitol, either material being commercially accepted in the confectionary art as sorbitol. Additionally, the sieve cut specifications given in the specification, e.g. "-20/+60 mesh cut," refer to stainless steel sieves of the U.S. Standard Screens.